1. Technical Field
The present invention relates to a resonator element, a resonator, an electronic device, an electronic apparatus, and a moving object.
2. Related Art
In small-sized information equipment such as a hard disk drive (HDD), a mobile computer, or an IC card, mobile communication equipment such as a cellular phone, a smartphone, or a tablet terminal, and so on, an electronic device such as a resonator or an oscillator is widely used as a device for providing a timing signal or a sync signal.
In the past, there has been known a device having a resonator element housed in a package as a resonator or an oscillator (see, e.g., JP-A-2006-345519 (Document 1)). The resonator element disclosed in Document 1 has a base section, two vibrating arms extending from the base section so as to be arranged in parallel to each other, and a support arm extending from the base section and located between the two vibrating arms in order to reduce the total length of the resonator element to achieve the miniaturization. Further, each of the vibrating arms has electrodes disposed respectively on four surfaces constituting the periphery of the vibrating arm, and each of the electrodes is connected to either one of two electrode pads disposed side by side on one of principal surfaces of the support arm and having respective polarities opposite to each other via a wiring pattern disposed on a side surface of the support arm. Such a resonator element is fixed to the package in the portions of the two electrode pads via an electrically-conductive adhesive, and is electrically connected to the electrodes on the package side.
Each of the electrodes, the wiring pattern, and the two electrode pads are formed using a photolithography technique and a wet-etching technique.
However, in some cases, the metal in an unwanted area among the metal deposited on the side surface of the support arm fails to be completely removed even using the photolithography technique and the wet-etching technique. In the resonator element disclosed in Document 1, there is caused a problem that the metal, in particular the metal in the area to be separated as opposite polarities in the wiring pattern, fails to be removed. In other words, since the side surface of the support arm is formed roughly perpendicularly to the principal surface roughly along the crystal Z axis of the quartz crystal, it is unachievable to successfully expose a resist film disposed on the surface of the metal thus deposited in the pattern formation of the side surface, and there is caused a problem that the metal in the area from which the metal should be removed fails to be removed as expected. As a result, since the metal which should be removed remains unremoved on the side surface of the support arm, there is a problem that it is unachievable to electrically separate the wiring pattern into the opposite polarities, and as a result the two electrode pads become short-circuited.
Therefore, in JP-A-2004-072609 (Document 2), there is described a technology of removing the metal in the area, which should electrically be separated, in the wiring pattern formed on the predetermined side surface of the resonator element by forming a cutout having a tilted surface.
If the technical concept described in Document 2 is applied to electrical separation of the wiring pattern formed on the side surface of the support arm, a shape shown in FIGS. 14A and 14B is expected. The support arm 23a of the second embodiment has a cut section 118a on the upper surface between first and second electrode pads 37, 38 disposed on the lower surface of the support arm 23a. The cut section 118a extends from a side surface 120a in the +X-axis direction of the support arm 23a toward the −X-axis direction, and is provided with a side surface 119c roughly perpendicular to the X axis, and a tilted surface 119a extending in the +X-axis direction as shown in FIG. 14B.
However, as shown in FIGS. 14A and 14B, since the depth of the tilted surface of the cut section becomes deep, it is necessary to increase the support arm in width direction as a result in order to ensure the strength, and there arises a problem that the miniaturization is difficult.